Resist pattern for alignment measurement

ABSTRACT

A resist pattern for alignment measurement being shrunk by a heat flow comprises a plurality of positive type or negative type line patterns. Widths of spaces between the line patters are greater than twice those of the line patterns. Alternatively, the resist pattern comprises a box-shaped or slit-shaped measurement pattern and a pair of box-shaped or slit-shaped auxiliary patterns provided inside and outside the measurement pattern, respectively.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a resist pattern used formanufacturing a semiconductor device and, especially, to a resist foralignment measurement with a pattern formed in the preceding processafter the resist pattern is formed for photolithography.

[0003] 2. Description of the Related Art

[0004]FIG. 8 shows the principal of alignment measurement according tothe conventional method. In FIG. 8, appropriate regions are selectedfrom a preceding pattern 10 formed in the preceding process, forexample, a box-shaped pattern 10 and a present pattern 100 beingprocessed at present, for example, a box-shaped pattern 100, so thatsymmetric waveforms are obtained from the regions by the waveformtreatment. The waveforms of the patterns 10 and 100 are recognized ordetected and graphically treated for linear approximation to obtain thepeak points of the preceding and present processes or steps. That is, aresist pattern for alignment measurement comprises the preceding boxpattern 10 provided at an outermost position and the present box pattern100 provided inside the box pattern 10 with a predetermined space.

[0005] Pattern recognition elements, for example, photo-sensors 100-104are arranged along a section A-A′, which is selected as an appropriateregion to obtain symmetric waveforms of the positive type box patternsof the preceding and present processes. The waveform signals of linepatterns at the section A-A′ are treated to obtain a characteristicB1-B1′. The characteristic B-B′ is treated in an alignment measuringapparatus to obtain a characteristic B2-B2′. That is, the line patterncontaining edges 10-1 and 10-2 becomes the characteristic B1-B1′containing points 10-3, 10-4, and 10-5 as a result of the treatment ofthe waveform signals and then, becomes the characteristic B2-B2′containing points 10-6, 10-7, and 10-8 as a result of the waveformtreatment in the alignment measuring apparatus.

[0006] Consequently, the line pattern containing the edges 10-1 and 10-2is characterized in that the concentration value thereof increaseslinearly up to the point 10-8 from the edge points 10-6 and 10-7. Thepoint 10-8 represents the central concentration value of the linepattern. The center of the characteristic pattern obtained by thewaveform treatment of the line pattern, such as the point 10-8, isreferred to as a “central point”.

[0007] In the same way, the box pattern 100 containing edges 100-1 and100-2 is changed to the characteristic B1-B1′ containing points 100-3and 100-4 by the waveform treatment at the section A-A′ and then,changed to the characteristic B2-B2′ containing points 100-5 and 100-6by the waveform treatment in the alignment measuring apparatus. That is,the edge 100-1 becomes the point 100-5 as a result of the waveformtreatment at the section A-A′.

[0008] The alignment measurement is performed by measuring at least oneplace, such as an interval between the points 10-8 and 100-5. In FIG. 8,two intervals are measured as shown by arrows Z in the characteristicB2-B2′. It is possible to select any place for X-direction andY-direction measurements as long as symmetric waveforms are obtained. Itis not necessary to measure in both the X and Y directions at eachmeasurement place and any combination of the X and Y directionmeasurements at different places is acceptable.

[0009] As a microscopic pattern is developed, a resist pattern (holepattern) produced by the ordinary KrF exposure/development method issubject to a baking process of high temperature to generate a heat flowin the resist pattern so that the internal diameter of the hole patternis reduced when the resist pattern is shrunk by the heat flow.

[0010]FIG. 10 shows the principal of pattern shrinkage by the heat flowaccording to the conventional method. A hole H having a circular sectionis provided in a resist pattern. The hole H before the heat flow shownon the left-hand side becomes a hole H′ shown on the right-hand sideafter the heat flow. An internal diameter a of the hole H is reduced bythe heat flow to an internal diameter a′ of the hole H′. This methodmakes it possible to manufacture a pattern of 0.10 μm or less, which ishigher than the resolution limit by the KrF exposure technology.

[0011] The method of reducing the hole diameter by the heat flow,however, has the following problems.

[0012] (1) If the resist pattern has a very large dimension before theheat flow, for example, if the hole internal diameter is 0.5 μm or more,the resist pattern deteriorates. That is, since the thickness of aresist film is substantially constant, the thickness b of the film at alinear section is reduced due to the increased amount of resist flown inthe hole when the hole internal diameter is larger than a certain value,thus causing adverse effects on the etching process after thephotolithography.

[0013] (2) How the pattern or hole is shrunk is dependent on other holesexist on the left and right-hand sides of the hole. That is, the form ofthe shrinkage by the heat flow is varies with the amount of the resistflown in the periphery of the hole. Where the holes exist densely, theresist amount per hole is small, which reduces the shrinkage of thepattern. This mechanism is described with aspect to FIG. 11.

[0014]FIG. 11 shows the symmetric character of the heat flow accordingto the prior art. A resist pattern having holes provided at the sameinterval and having the same diameter is heat-shrunk as described below.A hole A is uniformly shrunk on the upper, lower, and right sidesbecause of the presence of other holes, while the hole A is shrunk to alarger extent on the left side because of the larger amount of resistflow-in due to absence of other holes. Accordingly, the center of thehole A moves to the side of a hole B after the heat flow.

[0015] The hole B is uniformly shrunk on every side because of thepresence of other holes. A hole C is uniformly shrunk on the upper,lower, and left sides because of the presence of other holes, while thehole C is shrunk to a larger extent on the right side because of largeramount of flow-in resist due to absence of other holes. Consequently,the center of the hole C moves to the side of the hole B after the heatflow.

[0016] (3) A fine hole is not sufficiently shrunk unless the width of aspace between resist holes is greater than twice that of the resistholes before the heat flow. It is proved from the above-mentioned factthat unless holes are spaced from each other to a certain extent, theholes are not sufficiently shrunk and the sufficient height of thelinear section of the resist is not obtained due to a small amount offlow-in resist. Also, experiments show that desired characteristics areobtained when the width of a space between holes is greater than twicethat of the holes.

[0017] The results of the experiments are as follows:

[0018] (1) Object of the Experiments

[0019] To measure the conditions under which the thickness b of thelinear section in FIG. 10 becomes sufficiently practical after the heatflow.

[0020] (2) Conditions Resist: TDUR-P015 film thickness of 10,000 ÅReflection preventive film (bark material): Film thickness of 1,100 ÅSWK-EX2 NSG film film thickness of 10,000 Å Wafer: Si-substrate Exposureenergy 85 mj Manufacturing method heat shrinkage

[0021] (3) Layer Structure

[0022] TDUR-P015/SWK-EX2/NSG film/Si-substrate

[0023] (4) Results

[0024] When the hole diameter of a resist mask is fixed at 0.26 μm, thesamples having a hole pitch of 0.52 μm or more satisfied the aboveconditions. The samples having a hole pitch of 0.78 μm or 1.04 μm alsosatisfied the above conditions.

[0025] (4) Also, a large resist pattern, such as a pattern for alignmentmeasurement, loses the linearity of pattern edges after the heat flow.That is, every resist pattern in a wafer is shrunk as shown in FIG. 10regardless of the pattern size thereof since the heat flow is producedin the entire wafer. The pattern for alignment measurement requires arelatively large size because the alignment measurement is opticallyperformed. For a large pattern, as shown in FIG. 11, the amount offlow-in resist varies with the position thereof. For example, in thepresent pattern 100 in FIG. 9, the central portion of each side thereofundergoes the largest drift because of the largest amount of flow-outresist. Consequently, each side of the pattern is curved.

[0026]FIG. 9 shows a resist pattern for alignment measurement after theheat flow according to the prior art. Unlike the box pattern 100 in FIG.8, the present box pattern 100 is shrunk, when the heat flow treatmentis applied. When the resist pattern after the heat flow is subject tothe alignment measurement, the waveforms of preceding pattern or box 10and the present pattern or box 100 are processed to obtain the centralpoints of the patterns.

[0027] More specifically, the preceding box pattern 10 is provided atthe outermost side, and the present box pattern 100 is provided insidethe box pattern 10 at a predetermined interval. The photo-sensors101-104 for pattern recognition are arranged along the section A-A′. Theline patterns of the preceding positive type box pattern and a pluralityof the present positive type patterns at the section A-A′ are processedto obtain the characteristic B1-B1′, which in turn is processed in analignment measuring apparatus to obtain the characteristic B2-B2′.

[0028] That is, the line pattern containing edges 10-1 and 10-2 becomesthe characteristic B1-B1′ containing points 10-3, 10-4, and 10-5 as aresult of the process of the waveform signal, and then, thecharacteristic B-B′ is turned to the characteristic B2-B2′ containingpoints 10-6, 10-7, and 10-8 by the waveform-treatment in the alignmentmeasuring apparatus. Consequently, the line pattern at the section A-A′has the characteristic that the concentration value increases linearlyup to the point 10-8 from the edge points 10-6 and 10-7. The point 10-8represents the central concentration value of the center of the linepattern.

[0029] As shown in FIG. 9, the resist pattern or box is shrunk by theheat flow caused by a high temperature baking process so that thelinearity of the pattern edges is not maintained. That is, the sides ofthe box pattern under measurement are curved, forming arcs 120. Curvededges 120-1 and 120-2 of the box pattern 100 are turned to points 120-3and 120-4 in the characteristic B1-B1′ by the waveform treatment at thesection A-A′, and then, turned to points 120-5 and 120-6 in thecharacteristic B2-B2′ by the waveform treatment in the alignmentmeasuring apparatus. Consequently, the edge 120-1 becomes the point120-5. The measurement of an interval between the points 10-8 and 120-5represents the measurement of the position at which the present boxpattern 100 is curved and deformed by the heat flow.

[0030] In FIG. 9, a comparison between the characteristic B1-B1′ and thecharacteristic B2-B2′ shows that the shrinkage of the resist patternedge by the heat flow is a real problem. Especially, when the patternedges are measured on both the left and right-hand sides, an asymmetricwaveform signal is produced by the heat flow. When measured, theasymmetric waveform produces a deviation between the measured positionand proper position of the central point, thus producing an adverseeffect on the value of the alignment measurement.

[0031] As described above, the linearity of the present resist patternis broken by the heat flow. Consequently, the asymmetric waveform signalis processed, thus shifting the central position of the present pattern,causing an error in the alignment measurement.

SUMMARY OF THE INVENTION

[0032] Accordingly, it is an object of the invention to provide a resistpattern for alignment measurement, which maintains the symmetry of thetreatment signal of the pattern edge sections even after the heat flowprocess.

[0033] According to on aspect of the invention, there is provided aresist pattern for alignment measurement, which is shrunk by a heat flowand comprises a plurality of line patterns.

[0034] According to an embodiment of the invention, the line patternsare all positive types or negative types.

[0035] According to another embodiment of the invention, widths ofspaces between the line patters are greater than twice those of the linepatterns.

[0036] According to another aspect of the invention, there is provided aresist pattern for alignment measurement, which is shrunk by a heat flowand comprises a measurement pattern and a pair of auxiliary patternsprovided inside and outside the measurement pattern, respectively.

[0037] According to an embodiment of the invention, the measurement andauxiliary patterns are box-shaped or slit-shaped.

[0038] According to another embodiment of the invention, the measurementand auxiliary patterns are all positive types or negative types.

[0039] According to still another aspect of the invention, there isprovided a resist pattern for alignment measurement, which is shrunk bya heat flow and comprises a measurement pattern and at least oneauxiliary pattern provided inside or outside the measurement pattern,wherein widths of spaces between the measurement and auxiliary patternsare equal in vertical and horizontal directions.

[0040] According to yet another aspect of the invention, there isprovided a resist pattern for alignment measurement, which is shrunk bya heat flow and comprises a box-shaped measurement pattern and anauxiliary pattern provided outside said measurement pattern, whereinwidths of spaces between internal edges of the measurement pattern invertical and horizontal directions and widths of spaces between outeredges of the measurement pattern and inner edges of the auxiliarypattern in vertical and horizontal directions are all equal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041]FIG. 1 is a plan view of a resist pattern (positive type)according to the first embodiment of the invention.

[0042]FIG. 2 is a plan view of a resist pattern (negative type)according to the second embodiment of the invention.

[0043]FIG. 3 is a plan view of a resist pattern (positive type)according to the third embodiment of the invention.

[0044]FIG. 4 is a plan view of a resist pattern (negative type)according to the fourth embodiment of the invention.

[0045]FIG. 5 is a plan view of a resist pattern (positive type)according to the fifth embodiment of the invention.

[0046]FIG. 6 is a plan view of a resist pattern (positive type)according to the first embodiment of the invention.

[0047]FIG. 7 is a schematic diagram of a present pattern disposed atouter section according to the invention.

[0048]FIG. 8 is a plan view showing a theory of alignment measurementaccording to the prior art.

[0049]FIG. 9 is a plan view of a resist pattern for alignmentmeasurement after the heat flow according to the prior art.

[0050]FIG. 10 is a schematic diagram showing a principle of patternshrinkage by the heat flow according to the prior art.

[0051]FIG. 11 is a schematic diagram showing asymmetric characteristicsmade by the heat flow according to the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] Embodiments of the invention will now be described with referenceto the accompanying drawings.

[0053] (The First Embodiment)

[0054]FIG. 1 shows a resist pattern (positive type) according to thefirst embodiment of the invention. A box pattern 10 provided at anoutermost position is a resist pattern formed in a preceding process.Edges of a line pattern formed in the preceding process are measured bythe pattern measuring device to obtain a picture of the line pattern.

[0055] A plurality of patterns in the present process are provided inthree rows inside the box pattern 10. In the upper row, there areprovided horizontal line patterns 21, 22, and 23 having a predeterminedwidth and length. Spaces between the horizontal line patterns 21-23 havea predetermined width. In the intermediate row, there are providedvertical line patterns 24, 25, 26, 27, 28, and 29, each having apredetermined width and length. Spaces between the vertical linepatterns 24-29 have a predetermined width. In the lower row, there areprovided horizontal line patterns 30, 31, and 32, each having apredetermined width and length. Spaces between the horizontal linepatterns 30-32 have a predetermined width.

[0056] A relatively large pattern is required for the optical alignmentmeasurement. Accordingly, the resist pattern according to the firstembodiment is made as, for example, a positive type with a pattern sizegreater than 0.5 μm before the heat flow. The resist pattern comprisesat least three lines and spaces of the same size between the lines. Itis noted that the pattern size used in the first embodiment is not thepattern size of the hole in the above-mentioned prior art but thepattern size of the line.

[0057] The respective spaces have a width greater than twice the linewidth to obtain a stable resist form after the heat flow. The horizontalline patterns 21, 22, 23, 30, 31, and 32 are provided in parallel tohorizontal line sections of the preceding box pattern 10 and subject tothe alignment measurement in combination. The vertical line patterns24-29 are provided in parallel to vertical line sections of thepreceding box pattern 10 and subject to the alignment measurement incombination.

[0058] The horizontal and vertical line patterns 21, 32, 24, and 29provided at the outermost positions of each row are not used for thealignment measurement because the positions thereof are prone to theinfluences of the heat flow. Only the vertical line patterns 25, 26, 27,and 28 having circular marks may be used for measurement because theyare symmetric with respect to the section A-A′. In the first embodiment,the vertical line patterns 25 and 28 are used in combination with thevertical line sections of the preceding box pattern 10 for the alignmentmeasurement.

[0059] When the vertical section is used instead of the horizontalsection A-A′, any of the horizontal line patterns 22, 23, 30, and 31except the outermost horizontal patterns 21 and 32 are used asmeasurement patterns, and the remaining patterns are used as auxiliarypatterns. Widths of the spaces between the vertical and horizontal linepatterns are greater than twice those of the line patterns.

[0060] In the first embodiment, the pattern measuring elements, such asphoto sensors including photo transistors and photo diodes, are arrangedon the sectional line A-A′ at a predetermined interval. In FIG. 1, twosets of pattern measuring elements 33, 34, 35, and 36 are provided.Picture signals of a line pattern at the section A-A′ are obtained bythe pattern measuring elements 33, 34, 35, and 36. The picture signalsare transformed into the characteristic B-B′ by the waveform treatment.

[0061] Alignment measuring apparatus (not shown) is furnished withfunctions of designating a box for the waveform treatment and measuringand treating or processing the picture signals. An example of changingpatterns is described below.

[0062]FIG. 7 shows an example of disposing the present patterns at outerpositions. Four sets of present lines patterns 42, 43, 44, and 45, eachincluding three line patterns, are disposed in parallel to four sides ofthe preceding box pattern 40. The three line patterns are spaced fromeach other at a predetermined interval. When the preset patterns aredisposed outside the preceding pattern, at least three present patternsare required. The line patterns may be made positive or negative.

[0063] The alignment measuring apparatus designates a box to select aregion in which a symmetric waveform is obtained so that the waveform isdetected. The waveform is subject to linear approximation in thepicture-treatment device to obtain peak points of the preceding andpresent processes for the alignment measurement. Detailed description isas follows.

[0064] A plurality of positive type patterns are formed, and edges ofline patterns thereof at the section A-A′, at which the symmetry isobtained, are measured by the pattern measuring elements to obtain apicture of the line patterns. “The symmetry” means that the linepatterns have the same space and the same width on the opposite sides.In FIG. 1, the line patterns are arranged in a symmetric fashion withrespect to a central point between the vertical line patterns 26 and 27.Representative examples for the symmetric pattern are shown in FIGS. 3and 4.

[0065] The detected picture of the pattern edges along the line A-A′ ischanged to the characteristic B-B′ as a result of the waveformtreatment. In the characteristic B-B′, the concentration value isreduced in accordance with the transparent rate of the positive typeresist pattern. That is, the edges 10-1 and 10-2 of the line pattern arechanged to the points 10-3 and 10-4 in the characteristic B-B′,respectively. Consequently, the line pattern at the section A-A′including edges 10-1 and 10-2 has a characteristic that theconcentration value is increased linearly up to the point 10-5 from theedge points 10-3 and 10-4 in the characteristic pattern B-B′.

[0066] Similarly, the edges 25-1 and 25-2 of the vertical line pattern25 are changed to the points 25-3 and 25-4 in the characteristic B-B′,respectively, as a result of the waveform treatment of the detectedpicture signal at the section A-A′. The vertical line pattern 25 has acharacteristic that the concentration value is increased linearly up tothe point 25-5 from the edge points 25-3 and 25-4 in the characteristicpattern B-B′. The points 10-5 and 25-5 represents the concentrationvalues of the central position of the respective line patterns.

[0067] Alignment measurement is performed at least at one point. Forexample, the interval between the points 10-5 and 25-5 is measured. InFIG. 1, two points are measured as shown by the arrows Z. It is notnecessary to make both X-direction and Y-direction measurements at onemeasurement point. Any combination is acceptable. The same measurementis made to patterns in FIG. 7 in which the present pattern is disposedat an outer area. The outermost line patterns are not used for themeasurement since they are influenced by the heat flow.

[0068] Since the central positions of the edges are accurately measured,the alignment measurement is made accurate. Even when the presentpatterns are disposed outside the preceding patterns, the same effect aswhen the present patterns are disposed inside the preceding patterns isobtained if at least three present patterns are provided. The width ofthe spaces between the lines is greater than twice the width of lines soas to obtain the stable resist form after the heat flow.

[0069] (Second Embodiment)

[0070]FIG. 2 shows a resist pattern (negative type) according to thesecond embodiment of the invention. The second embodiment employsnegative type patterns, while the first embodiment employs positive typepatterns. When the waveform treatment of a picture of the negative typepatterns at the section A-A′ is made, a reverse of the characteristicB-B′ of the positive type patterns is obtained. The alignmentmeasurement is performed in the same way. The second embodiment has thesame effects as those of the first embodiment.

[0071] (Third Embodiment)

[0072]FIG. 3 shows a resist pattern (positive type) according to thethird embodiment of the invention. The preceding box pattern 10 isprovided at the outermost position. Present box patterns 51, 52, and 53having similar shapes are disposed inside the box pattern 10 at apredetermined interval. The box patterns 51-53 are spaced from eachother at a predetermined distance. The width of spaces is made greaterthan twice the width of lines on the sides of the box patterns.Auxiliary patterns 51 and 53 are provided inside and outside themeasurement pattern 52, respectively. The auxiliary patterns 51 and 53are made with a pattern size smaller than that of the measurementpattern 52. Spaces between the patterns have a width greater than twicethe width of lines of the measurement pattern 52.

[0073] The purpose of providing the auxiliary pattern is to adjust theamount of resist which flow in or out so that the alignment measurementof the measurement pattern after the heat flow is made accurate. It isnot necessary to take optical date of the auxiliary patterns since thedata is not used for the measurement. Even if the auxiliary patterns areburied and disappears after the heat flow, it presents no problem.

[0074] The reason that the auxiliary patterns are made with a patternsize smaller than that of the measurement pattern is that if theauxiliary pattern is excessively large, the increased amount of flow-inresist deforms the form of the auxiliary pattern.

[0075] Mask size spaces have the same width inside and outside, upperand lower sides, and left and right sides so that the form of themeasurement pattern after the heat flow is uniform.

[0076] In FIG. 3, photo sensors 54, 55, 56, and 57 for picture detectionare arranged along the section A-A′. The measurement pattern 52 is madewith a pattern size greater than 0.5 μm, for example, to avoidexcessively small pattern size before the heat flow. The positive typepatterns 51 and 53 having a plurality of lines and spaces of the samedimension are provided inside and outside the pattern 52, respectively.The spaces have widths greater than twice those of lines so as to obtaina stable resist form after heat flow.

[0077] In measurement of the preceding positive type box pattern and aplurality of the present positive type patterns, edges of the linepatterns symmetrical with respect to the section A-A′ are measured toobtain pictures thereof. The pictures are waveform-treated to obtain thecharacteristic B-B′. The edges 10-1 and 10-2 of the line pattern arechanged to the points 10-4 and 10-5 in the characteristic B-B′,respectively. Consequently, the line pattern 10 at the section A-A′including the edges 10-1 and 10-2 has a characteristic that theconcentration value thereof increases linearly up to the central point10-5 from the edge points 10-3 and 10-4.

[0078] Similarly, the measurement pattern 52 at the section A-A′including the edges 52-1 and 52-2 has a characteristic that theconcentration value thereof increases linearly up to the point 52-5 fromthe edge points 52-3 and 52-4. The points 10-5 and 52-5 represent theconcentration values of the central points of the respective linepatterns.

[0079] The alignment measurement is performed at least at one point, forexample, the interval between the points 10-5 and 52-5 is measured. InFIG. 3, two points are measured as shown by the arrows Z. It is notnecessary to make measurements on both X and Y directions for eachmeasurement point but any combination of the measurements is acceptable.

[0080] It is possible to prevent the position of the central point ofthe resist pattern for the alignment measurement from moving after theheat flow.

[0081] (Fourth Embodiment)

[0082]FIG. 4 shows a resist pattern (negative type) according to thefourth embodiment of the invention. The fourth embodiment employsnegative type patterns, while the third employs the positive typepatterns. A plurality of negative type box patterns including auxiliarypatterns are provided. The auxiliary patterns are made with a patternsize smaller than that of the measurement pattern. The space width isgreater than twice the line width of the measurement pattern. The widthsof mask size spaces at inside and outside, upper and lower sides, andleft and right sides are all made equal.

[0083] The form of the resist pattern after the heat flow is sosymmetric that the position of the central point of the measurementpattern is unchanged after the heat flow treatment. The waveformtreatment of the characteristic B-B′ of the negative type pattern at thesection A-A′ is a reverse of the characteristic B-B′ of the positivetype pattern. The alignment measurement is performed in the same way.

[0084] The fourth embodiment has the same effects as those of the thirdembodiment. That is, it is possible to prevent the position of thecentral point of the resist pattern for alignment measurement from beingchanged by the heat flow treatment.

[0085] (Fifth Embodiment)

[0086] The fifth embodiment comprises positive type or negative typeauxiliary patterns, such as, slits or lines patterns, while the thirdand fourth embodiments comprise box patterns as the auxiliary patterns.The slit patterns are provided to adjust the amount of resist whichflows in or out so as to make accurate alignment measurement of themeasurement pattern after the heat flow. An example of the positive typepattern is described below.

[0087]FIG. 5 shows a positive type resist pattern according to the fifthembodiment. A measured box pattern 72 having a similar shape as that ofthe preceding box pattern 10 is provided inside the preceding boxpattern 10. Slit patterns 73, 74, 77, and 78 are provided in a spacebetween the preceding box pattern 10 and the measured box pattern 72 inparallel with sides of the respective box patterns 10 and 72. Anauxiliary pattern formed of two slit patterns 75 and 76 crossing eachother is provided inside the measurement pattern 72.

[0088] The auxiliary patterns 73, 74, 77, 78, 75, and 76 may be linepatterns instead of slit patterns. The auxiliary patterns 73-78 and themeasurement pattern 72 are positive types. However, the above patternsmay be made negative types.

[0089] (Measuring Operation)

[0090] The slit patterns 73-76 are provided inside and outside thepositive type measurement pattern 72 as auxiliary patterns. Theseauxiliary patterns 73-76 are made with a pattern size smaller than thatof the measurement pattern 72. A space width is made greater than twicethe line width of the measurement pattern 72. Widths of the mask sizespace at inside and outside, upper and lower sides, left and right sidesare all equal.

[0091] In FIG. 5, photo sensors 79, 80, 81, and 82 are arranged alongthe section A-A′. Edges of line patterns at the section A-A′ aremeasured by the photo sensors 79-82 so as to obtain pictures of the linepatterns. The detected pictures are changed to the characteristic B-B′by the waveform treatment. In the characteristic B-B′, the concentrationvalue decreases in accordance with the transparency rate of the positivetype patterns. The edges 10-1 and 10-2 of the line pattern become thepoints 10-3 and 10-4 in the characteristic B-B′ by the waveformtreatment. Consequently, the line pattern including the edges 10-1 and10-2 at the section A-A′ has a characteristic that the concentrationvalue thereof increases linearly up to the central point 10-5 from theedge points 10-3 and 10-4.

[0092] Similarly, the measurement pattern 72 at the section A-A′including the edges 72-1 and 72-2 has a characteristic that theconcentration value thereof increases linearly up to the point 72-5 fromthe edge points 72-3 and 72-4. The points 10-5 and 72-5 represent theconcentration values of the central points of the respective linepatterns.

[0093] The alignment measurement is performed at least at one point, forexample, an interval between the 10-5 and 72-5 is measured. In FIG. 5,two points are measured as shown by the arrows Z. It is not necessary tomake measurements in both X and Y directions at each measurement pointbut any combination of the measurements is acceptable.

[0094] In FIG. 5, the resist pattern form after the heat flow treatmentis symmetric. Accordingly, the position of the central point of themeasurement patterns is not changed by the heat flow treatment so thatthe edge shape of the resist pattern is not changed after the heat flowtreatment. The auxiliary pattern may be made with any pattern size asfar as it is made smaller than the measurement pattern. However, if theauxiliary pattern is made excessively large, the increased amount of theflown-in resist deforms the auxiliary pattern.

[0095] (Sixth Embodiment)

[0096]FIG. 6 shows a resist pattern (positive type) according to thesixth embodiment. In the sixth embodiment, an auxiliary pattern is notlarger than a measurement pattern. The preceding pattern 10 is providedat the outermost position. Box patterns 92 and 93 having a similar shapeas that of the preceding pattern 10 are provided inside the precedingpattern 10 at a predetermined interval. The box patterns 92 and 93 arespaced from each other with a predetermined space width. The space widthis set larger than twice the line width of sides of the box patterns.The box pattern 92 is an auxiliary pattern, while the box pattern 93 isa measurement pattern.

[0097] The auxiliary pattern 92 is provided outside the positive typemeasurement pattern 93. The auxiliary pattern 92 is made with a patternsize smaller than that of the measurement pattern 93. Space widths ofmask size at inside and outside, upper and lower sides, and left andright sides are all made equal. Photo sensors for recognizing a pictureof the measurement pattern are arranged, for example, along the sectionA-A′. In FIG. 6, photo sensors 54, 55, 56, and 57 are arranged along thesection A-A′.

[0098] Negative type patterns, which are made with a pattern sizegreater than 0.5 μm, for example, to avoid excessively small patternsize and include a plurality of lines having the same size and spaces ofthe same size, are provided. The spaces have a width greater than twicethat of lines so as to obtain a stable resist form after the heat flow.

[0099] An inside opening of the measurement pattern 93 has a verticaldimension of d and a horizontal dimension of a. Vertical and horizontaldistances between an outer edge of measurement pattern 93 and an inneredge of the auxiliary pattern 92 are c and d, respectively.

[0100] If the patterns are disposed such that the formula a=b=c=d ismaintained, it is sufficient that one auxiliary pattern is providedinside or outside the measurement pattern. The formula a=b=c=d meansthat left and right sides are symmetric. The pattern according to thesixth embodiment may be made a negative pattern instead of a positivepattern.

[0101] In the same way as that of the preceding embodiments, thepreceding pattern 10 and the present positive type pattern 93 become thecharacteristic B-B′. The box pattern 92 is an auxiliary pattern. Thatis, the edges 10-1 and 10-2 of the line pattern 10 becomes the points10-3 and 10-4 in the characteristic B-B′, respectively. Consequently,the line pattern 10 at the section A-A′ after the waveform treatment hasa characteristic that the concentration value increases linearly up tothe central point 10-5 from the points 10-3 and 10-4.

[0102] Similarly, the box pattern 93 including edges 93-1 and 93-2 atthe section A-A′ has a characteristic, after the waveform treatment,that the concentration value increases linearly up to a central point93-5 from points 93-3 and 93-4. The points 10-5 and 93-5 represent theconcentration value of the central position of the respective linepatterns.

[0103] The alignment measurement is performed at least at one place, forexample, an interval between the points 10-5 and 93-5. In FIG. 6, twoplaces are measured as shown by the arrows Z. It is not always necessaryto measure in both X and Y directions at each measurement place but anycombination of measurements is acceptable.

[0104] The positions of the central points of the patterns are notchanged by the heat flow treatment because the shapes of the patternsare symmetric even after the heat flow treatment. Also, the number ofthe auxiliary patterns can be reduced.

[0105] (Other Embodiments)

[0106] In the above-mentioned embodiments, the invention is applied tothe resist pattern for the alignment measurement. However, the inventionis applicable to a resist pattern for improving the detection accuracyfor an alignment mark or positioning mark in other semiconductormanufacturing apparatus.

[0107] According to the invention, a resist pattern for alignmentmeasurement remains symmetric in the picture treatment signal of patternedges even after the heat flow treatment. Also, the resist pattern has astable shape after the heat flow treatment.

1. A resist pattern for alignment measurement, said resist pattern beingshrunk by a heat flow, comprising: a plurality of line patterns.
 2. Theresist pattern for alignment measurement according to claim 1, whereinsaid line patterns are all positive types.
 3. The resist pattern foralignment measurement according to claim 1, wherein said line patternsare all negative types.
 4. The resist pattern for alignment measurementaccording to claim 1, wherein widths of spaces between said line pattersare greater than twice those of said line patterns.
 5. A resist patternfor alignment measurement, said resist pattern being shrunk by a heatflow, comprising: a measurement pattern; and a pair of auxiliarypatterns provided inside and outside said measurement pattern,respectively.
 6. The resist pattern for alignment measurement accordingto claim 5, wherein said measurement and auxiliary patterns arebox-shaped.
 7. The resist pattern for alignment measurement according toclaim 5, wherein said measurement and auxiliary patterns areslit-shaped.
 8. The resist pattern for an alignment measurementaccording to claim 5, wherein said measurement and auxiliary patternsare all positive types.
 9. The resist pattern for an alignmentmeasurement according to claim 5, wherein said measurement and auxiliarypatterns are all negative types.
 10. A resist pattern for alignmentmeasurement, said resist pattern being shrunk by a heat flow, comprisinga measurement pattern; and at least one auxiliary pattern providedinside or outside said measurement pattern, wherein widths of spacesbetween said measurement and auxiliary pattern are equal in vertical andhorizontal directions.
 11. A resist pattern for alignment measurement,said resist pattern being shrunk by a heat flow, comprising a box-shapedmeasurement pattern; and an auxiliary pattern provided outside saidmeasurement pattern, wherein widths of spaces between internal edges ofsaid measurement pattern in vertical and horizontal directions andwidths of spaces between outer edges of said measurement pattern andinner edges of said auxiliary pattern in vertical and horizontaldirections are all equal.